禽蛋破损在线检测自动敲击发声装置设计与试验

针对禽蛋破损在线检测技术要求，设计了一种轻巧的自动敲击发声装置，该装置利用电磁吸合原理，由单片机控制线圈中电流的方向和大小变化，改变感应区的磁场方向和磁场强度，控制敲击杆的伸出、停止和返回，从而实现对蛋壳的敲击发声，密闭在敲击杆内部的麦克风采集声音信号。对自动敲击发声装置的结构和工作原理、硬件参数及软件实现进行了描述，并以鸡蛋为对象，进行了声音信号采集试验。结果表明：该装置运行稳定，反应迅速，敲击准确率达到了100%，而且敲击力度适中，敲击引起的蛋壳损伤率为0，采集的声音信号实时、清晰，为改善禽蛋无损检测装备性能提供了参考。

Design and experiment of automatic knocking device for eggshell crack detection

In order to meet the requirements of eggshell crack detection for on-line application, an automatic knocking device was designed, which can make an impact on eggshell without any damage and collect the vibration signal from the egg surface through a microphone placed in the center of the automatic knocking device during the exciting time. The structure and working principle of the device, operating parameters and software working flow were introduced in the paper. And the experiment of vibration signal collecting on eggs was carried out. The test results show that the system runs steadily and reacts swiftly, the accuracy ratio of knocking can reach 100%, and the mechanical impact was so moderate that there would not be any new crack on eggshell. It should be highlighted that the microphone can record the real time signals clearly.